Ceramic substrate, EDX, Si MappingNonwoven Ceramic substrate S UMMARY Experimental Bead milling and Stirring Coating Drying and Gelation Ceramic porous substrate Preparation of solution Ethanol, GPTMS, SiO 2 particles, HNO 3 TSC : 10wt% For 1.5h, Sol formation Coating of silica sol to nonwoven matrix Formation of silica networks via gelation Impregnation Acidification and Rinsing Ceramic substrate-reinforced SPAES composite membranes 5wt % SPAES-50 Solution in DMAc H 2 SO 4, D.I water  Properties of nonwoven and ceramic substrate  Classification of membrane  Ceramic porous substrates  Ceramic substrate-reinforced SPAES composite membranes  Morphology of composite membranes  SPAES-50 (sulfonated poly(arylene ether sulfone), D.S = 50%)  Dimensional stability  Characterization of water state  Proton conductivity  We developed the new ceramic substrates for reinforced proton conducting membranes, which consisted of GPTMS/SiO 2 -based ceramic and nonwovens.  The ceramic substrates showed the improved mechanical strength, while maintaining the highly porous structure that is filled with proton-conducting polymers of SPAES-50.  These unique advantages of the ceramic substrates allowed the ceramic substrate-reinforced SPAES composite membranes to significantly suppress the dimensional change.  The ceramic substrate-reinforced SPAES composite membranes offered the superior water-retention capability, which led to the improved proton conductivity at low humidity. A SiO 2 Ceramic Porous Substrate-Reinforced Sulfonated Poly(arylene ether sulfone) Composite Membrane for a Proton Exchange Membrane Fuel Cell Ji-Hye Won, Sang-Young Lee * Energy Materials Lab., Department of Chemical Engineering, Kangwon National University Results Introduction Ref : Adv. Mater. 2007, 19, 592–596 Ref. 1 J. Power Sources 150 (2005) 11–19 SEM image of surface of porous PTFE membrane ①② Ref. 2 Electrochimica Acta 52 (2007) 5304–5311 SEM image of the ePTFE matrix:  Reinforcing substrates : PTFE, PE, PP, etc. Extremely hydrophobic Weak mechanical stability Inert proton-conductor  Previous studies  Improved interfacial adhesion with proton conductor : Pinhole-free impregnation / Long-term durability  Ceramic substrates : Mechanical / Dimensional stability  Hygroscopic inorganic materials : Strong water retention capability Ref. J. Membr. Sci. 306 (2007) 298–306 The cross-section micrographs of the composite PEMs  Objectives of this study  Morphology (FE-SEM image, EDX)  Wetting Test (Water) SPAES membrane Composite membrane State of water RT ~ 100 ℃, weight loss (wt%) Physically adsorbed water 100 ℃ ~ water content weight loss (wt%) Chemically adsorbed water Water content at 25 ℃, 50%RH (wt%) Dry Wet SPAES Membrane  A = 112 % Composite Membrane  A < 10 %  Pore size distribution 100 RH% 30 ℃, 50 RH% SPAES Nonwoven SPAES Impregnation SiO 2 Nanoparticles GPTMS Samples Thickness ( ㎛ ) Porosity (%) Tensile Strength (MPa) Tensile Modulus (MPa) Nonwoven Ceramic Substrate Ceramic SubstrateNonwovenCeramic SubstrateNonwoven BeforeAfter 100 μm 5 μm 500 nm 200 μm 50 μm 1 μm 50 μm EDX, Si mapping Si Cross section 65 ℃, 50 RH% Chemically Adsorbed Water Physically Adsorbed Water